R24FXX-EC FeaturesThe Rhino R24FXX-EC PCI analog card features a control element to remove all "bit banging" on the PCI bus, something that other manufacturer's have yet to solve! This Rhino feature significantly reduces PCI and CPU overhead.Hosts up to twelve, dual channel FXS or FXO modular cards, using one RJ21 female connectorFXS channels utilize the Infineon PEB3268 ringing SLIC single chipFXO channels utilize the Silicon Labs Si3050 and Si3019 DAA chipsetUser upgradeable, modules snap on and off easily, yet are rigorously held in place both electrically and mechincally